Breathing assistance apparatus

ABSTRACT

A mask assembly for use as part of an apparatus for supplying a flow of respiratory gases to a user is disclosed. The mask assembly includes a mask body having an inlet through which said flow of respiratory gases are provided to the interior of said mask body. A mask seal assembly comprising a seal of flexible material and a clip of rigid material is attached to the body. The seal has a first side and a second side. The first side of the seal is shaped to approximately match the contours of a user&#39;s face and in use substantially seal against a user&#39;s face. The second side is attached to the clip. The clip provides an interface extending substantially the full perimeter or periphery of the mask seal assembly for releasably attaching the mask seal assembly to the mask body. The clip comprises a bridging portion spanning outwards from the perimeter or periphery of the mask body to space at least a portion of the second side of the seal outwards from the perimeter or periphery of the mask body.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention generally relates to patient interfaces. Moreparticularly, the present invention relates to such interfacesparticularly though not solely for use in delivering CPAP therapy topatients suffering from obstructive sleep apnoea (OSA).

Description of the Related Art

In the art of respiration devices, there are a variety of respiratorymasks that cover the nose and/or mouth of a human user in order toprovide a continuous seal around the nasal and/or oral areas of the facesuch that gas may be provided at positive pressure within the mask forconsumption by the user. The uses for such masks range from highaltitude breathing (i.e., aviation applications) to mining and firefighting applications, to various medical diagnostic and therapeuticapplications.

Such respiratory masks should provide an effective seal against theuser's face to reduce the likelihood of leakage of the gas beingsupplied. Commonly, in prior mask configurations, a good mask-to-faceseal has been attained in many instances only with considerablediscomfort for the user. This problem is prevalent in thoseapplications, especially medical applications, in which the user wears amask or patient interface continuously for hours or perhaps even days.In such situations, the user may not tolerate the mask for longdurations and optimum therapeutic or diagnostic objectives thus will notbe achieved, or will be achieved with great difficulty and considerableuser discomfort.

To aid with user comfort, masks can be provided in a range of differentsizes. A user will find one particular size in the available range ofsizes most suitable for providing an effective seal and a comfortablefit. A single mask frame can be provided to which a range of differentsized seals may be fitted. A user chooses the most suitably sized sealfrom the available range (e.g., the user chooses one size from small,medium, large and extra large) and attaches that seal to the mask framefor use.

A further example of a way in which differently sized users areaccommodated is the nasal mask range disclosed in US2010/0006101, theentire contents of which are hereby incorporated by reference herein. Asshown in FIG. 1 of this application, three different sized mask bodies430 and correspondingly sized seal assemblies 440 are provided. A usermay select the most suitably sized frame and corresponding seal assemblyfor use. Various components of the nasal mask disclosed inUS2010/0006101 are described below with reference to FIGS. 2 to 6.

The mask assembly 402 comprises a mask body 430 and a mask seal assembly440. The mask body 430 provides the overall structural support for themask assembly, and provides a clip type fitting 433 for attaching themask assembly 402 to headgear 421. The mask body includes a foreheadsupport 431 to which the headgear is also attached.

A rear side of the mask body 430 interfaces to the seal assembly 440.The seal assembly 440 provides a sealing interface against a user's facein use.

The mask body 430 has an inlet for receiving a flow of respiratory gasesand exhaust holes 425 to allow exhaled breath to be vented from the maskassembly. The mask body forms an internal cavity to which respiratorygases are supplied via the inlet. The inlet comprises a tubularprojection 422 extending from a front side 471 of the mask body 430. Aconnector 423 connects to the inlet and swivels with respect to the maskbody 430, for connecting a supply conduit to the mask body.

The seal assembly 440 comprises a flexible seal 443 attached to arelatively rigid plastic clip 442. The flexible seal 443 is over-mouldedto the plastic clip 442 so that the seal assembly 440 forms a singleitem of the mask assembly 402. The plastic clip has a series of holes446 around its perimeter. During manufacture, over moulding of the sealto the clip causes the seal material to flow through the series of holes446. During manufacture, the seal material is cured. Once cured, theseal 443 is mechanically linked to the plastic clip 442 via holes 446,providing a mechanical joint between the clip and the seal. The holes446 are located through a raised ridge 445 running around the insideperimeter of the clip.

The clip 442 releasably attaches to the mask body in a ‘clip’ or ‘snap’type engagement. A series of bumps 448, or raised portions, on the maskbody 430 interact with corresponding recesses 447 on the clip 442, tohold the clip 442 in place on the body 430. As the clip 442 attaches tothe mask body, interference between the clip and each mask body bump 448causes the clip or the mask body, or both, to deflect to a deflectedcondition until each bump 448 reaches a corresponding recess 447. Oncethe clip has been fully engaged with the body, each bump 448 locateswithin a corresponding recess 447, and the clip or body, or bothun-deflect from the deflected condition to an un-deflected or partiallydeflected condition, the parts being clipped or snapped together in afully engaged position.

The clip 442 preferably has a relatively long lead in, or ramped profile449, leading to the clip recess 447. This lead in section extends thefull inside perimeter length of the clip 442. The lead-in sectionassists with the attachment of the clip to the mask body. The clip 442or mask body 430, or both, are gradually deflected over the length ofthe lead-in section until the apex of the lead-in section and each maskbody bump 448 pass each other. Once the bumps 448 have passed over thelead-in section, the bumps 448 locate within each corresponding recess447, such that there is little or no interference between the two parts430 and 442. The two parts un-deflect in a relatively sudden snap actioncompared to the gradual deflection caused by the lead in section 449during engagement.

The face seal assembly 440 includes at least one wing portion 444 toassist a user to disengage the face seal assembly from the mask body.The wing portions 444 provide a gripping flange to pull the clip 442away from the mask body 430.

The nasal mask includes a cushion 441. Cushion 441 is provided aroundthe periphery of the mask, and is surrounded by the seal assembly 440.The cushion 441 provides support to the seal 443 to achieve an effectiveseal onto the face of the user to reduce the likelihood of leakage.

One end 462 of the mask cushion is shaped to match the shape of the sealin contact with the user's face, and an opposite end 463 is shaped tomatch the mask body. The cushion includes a raised bridge 465 in thenasal bridge region. The raised bridge 465 can also be described as acut out section made in the cushion, the cut out being on the mask bodyend 463 of the cushion. As the raised bridge 465 is unsupported by themask body 430, it is much more flexible and results in less pressure onthe nasal bridge of the patient.

The cushion 441 is located around the outer periphery of the mask body,contacting the mask body except for in the raised bridge portion 465 ofthe cushion. The cushion is located in a generally triangular cavity466, the cavity continuing around the periphery of the body, terminatingat each side of the nose bridge region 467 of the mask, where the raisedbridge portion 465 of the cushion does not contact the mask body 430.The cavity 466 is generally formed by two spaced apart walls 476 and477. The cushion 441 is a separate item, the seal assembly 440 fittingin place over the cushion to hold it in place within the mask assembly402.

In this specification where reference has been made to patentspecifications, other external documents, or other sources ofinformation, this is generally for the purpose of providing a contextfor discussing the features of the invention. Unless specifically statedotherwise, reference to such external documents is not to be construedas an admission that such documents, or such sources of information, inany jurisdiction, are prior art, or form part of the common generalknowledge in the art.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a patient interfacewhich goes some way to overcoming disadvantages in the prior art orwhich will at least provide the users with a useful choice.

In one aspect, the present invention broadly consists in a mask assemblyfor use as part of an apparatus for supplying a flow of respiratorygases to a user, comprising:

a mask body having an inlet through which said flow of respiratory gasesare provided to the interior of said mask body, the inlet adapted to beconnected to a gases conduit,

a mask seal assembly comprising a seal of flexible material and a clipof rigid material,

the seal having a first side and a second side, the first side of theseal being shaped to approximately match the contours of a user's faceand in use substantially seal against a user's face, the second sideattached to said clip,

the clip providing an interface extending substantially the fullperimeter or periphery of the mask seal assembly for releasablyattaching the mask seal assembly to the mask body, and

wherein the clip comprises a bridging portion spanning outwards from theperimeter or periphery of the mask body to space at least a portion ofthe second side of the seal outwards from the perimeter or periphery ofthe mask body.

Preferably the mask assembly comprises an inner cushion located betweenthe clip and the first side of the seal.

Preferably the inner cushion is located between the bridging portion ofthe clip and the first side of the seal.

Preferably the clip comprises a channel in the bridging portion, a firstside of the inner cushion in use supporting the first side of the seal,and a second side of the inner cushion being received in the channel.

Preferably the seal is attached to a first side of the clip and a secondside of the clip releaseably attaches to the mask body, and the bridgingportion spans between the first and second sides of the clip.

Preferably the seal assembly comprises a second seal of flexiblematerial attached to the second side of the clip for forming a sealbetween the mask seal assembly and the mask body.

Preferably the bridging portion and the seal are sized according to oneof a series of sizes, each one of the series of sizes suitable forsealing against a differently sized user's face.

Preferably the mask body is adapted for use with a plurality of the sealassemblies, at least one said seal assembly having a said bridgingportion, each said seal assembly having a said seal sized according toone of a series of sizes, each one of the series of sizes suitable forsealing against a differently sized user's face, and the second side ofthe clip of each said seal assembly being the same or similar to bereleasably attached to the mask body.

Preferably the seal and the second seal are integrally formed and joinedtogether across the bridging portion.

Preferably the seal and the second seal are integrally formed and joinedtogether across the bridging portion via a runner across or through thebridging portion.

Preferably the mask assembly comprises an inner cushion located betweenthe mask body and the first side of the seal.

Preferably the mask assembly comprises a channel in the mask body, afirst side of the inner cushion in use supporting the first side of theseal, and a second side of the inner cushion being received in thechannel in the mask body.

Preferably the bridging portion has an outward dimension that is thesame or similar around the perimeter or periphery of the mask body.

Preferably the bridging portion has an outward dimension that variesaround the perimeter or periphery of the clip.

Preferably the outward dimension of the bridging portion is larger at abottom portion of the seal assembly and smaller at an upper portion ornasal bridge region of the seal assembly.

Preferably the bridging portion tapers from a first outward dimension inthe bottom portion of the mask assembly to a second outward dimension inthe upper portion or nasal bridge region of the mask assembly.

Preferably each said seal assembly in the said plurality of sealassemblies has a bridging portion with a first outward dimension in thebottom of the mask assembly and a second outward dimension in the upperportion of the mask assembly and the first outward dimension is greaterthan the second outward dimension, and the second outward dimension ofeach said seal assembly is the same or similar, and the first outwarddimension of each said seal assembly is different to the first outwarddimension of the other said seal assemblies in said plurality of sealassemblies, the first outward dimension of each said seal assembly sizedto be suitable for sealing against a differently sized user's face.

Preferably the bridging portion extends rearward away from a front ofthe mask body towards a user's face in use.

Preferably the mask body is adapted for use with a plurality of the sealassemblies, at least one said seal assembly having a said bridgingportion, each said seal assembly having a seal of a different typecomprising one of a cannula seal, a nasal seal, a mouth seal and a fullface seal, and the second side of the clip of each said seal assemblybeing the same or similar to be releasably attached to the mask body.

Preferably the mask seal assembly releasably attaches to a rearperimeter of the mask body.

Preferably the rear perimeter of the mask body defines an area beingmore than ten times the area of the mask body inlet.

Preferably the bridging portion spaces the second side of the sealoutwards from the perimeter or periphery of the mask body by at least 10mm.

Preferably the mask body defines a hollow space for receiving orcovering a user's nose or mouth or both.

In another aspect, the present invention broadly consists in a maskpackage comprising:

a mask body having an inlet through which a flow of respiratory gasesare provided to the interior of the mask body, the inlet adapted to beconnected to a gases conduit,

a first seal assembly comprising:

a first seal of a flexible material and a first clip of a rigidmaterial, the first seal having a first side and a second side, thefirst side of the first seal being shaped to approximately match thecontours of a user's face and in use substantially seal against a user'sface, said second side of said first seal attached to said first clip,

the first clip providing an interface extending substantially the fullperimeter or periphery of the first seal assembly, the second side ofthe first seal attached to a first side of the first clip and a secondside of the first clip for releaseably attaching the first seal assemblyto the mask body,

a second seal assembly comprising:

a second seal of a flexible material and a second clip of a rigidmaterial, the second seal having a first side and a second side, thefirst side of the second seal being shaped to approximately match thecontours of a user's face and in use substantially seal against a user'sface, said second side of said second seal attached to said second clip,

the second clip providing an interface extending substantially the fullperimeter or periphery of the second seal assembly, the second side ofthe second seal attached to a first side of the second clip and a secondside of the second clip for releaseably attaching the second sealassembly to the mask body,

wherein the first clip or the second clip or both comprises a bridgingportion spanning outwards from the perimeter or periphery of the maskbody to space at least a portion of the second side of the first orsecond seal outwards from the perimeter or periphery of the mask bodywhen the first or second seal assembly is attached to the mask body, andthe first side of the first clip being comparatively different to thefirst side of the second clip, and the first seal being comparativelydifferent to the second seal.

Preferably the mask package comprises a first inner cushion for use withthe first seal assembly and a second inner cushion for use with thesecond seal assembly.

Preferably the first seal assembly attached to the mask body, the firstinner cushion is located between the first clip and the first side ofthe first seal, or with the second seal assembly attached to the maskbody, the second inner cushion is located between the second clip andthe first side of the second seal.

Preferably the first seal assembly attached to the mask body, the firstinner cushion is located between the bridging portion of the first clipand the first side of the first seal, or with the second seal assemblyattached to the mask body, the second inner cushion is located betweenthe bridging portion of the second clip and the first side of the secondseal.

Preferably the bridging portion of the first clip of the first sealassembly has a channel for receiving the first inner cushion, or/and thebridging portion of the second clip of the second seal assembly has achannel for receiving the second inner cushion.

Preferably the bridging portion of the first clip of the first sealassembly has an outward dimension that varies around the perimeter ofthe first clip, or the bridging portion of the second clip of the secondseal assembly has an outward dimension that varies around the perimeterof the first clip.

Preferably the bridging portion of the first clip of the first sealassembly has a larger outward dimension at the bottom of the first sealassembly compared to the outward dimension at the top or nasal bridgeregion of the first seal assembly, and/or the bridging portion of thesecond clip of the second seal assembly has a larger outward dimensionat the bottom of the second seal assembly compared to the outwarddimension at the top or nasal bridge region of the second seal assembly.

Preferably the bridging portion of the second clip of the second sealassembly has a larger outward dimension at the bottom of the second sealassembly compared to the bridging portion of the first clip of the firstseal assembly, the second seal of the second seal assembly being largerthan the first seal of the first seal assembly.

Preferably the bridging portion of the first clip of the first sealassembly and the bridging portion of the second clip of the second sealassembly have the same or a similar outward dimension in the nasalbridge region of the clip.

Preferably the first side of the second seal has a longer perimeterlength than the first side of the first seal.

Preferably a mask assembly comprising the mask body and the first sealassembly has an internal cavity having a first depth, and a maskassembly comprising the mask body and the second seal assembly has aninternal cavity having a second depth, the second depth being greaterthan the first depth.

Preferably the bridging portion of the second clip of the second sealassembly extends rearward away from the general plane of the mask bodywhen the second seal assembly is attached to the mask body.

Preferably the first seal assembly comprises a seal of flexible materialattached to the second side of the first clip for forming a seal betweenthe first mask seal assembly and the mask body, and/or

the second seal assembly comprises a seal of flexible material attachedto the second side of the second clip for forming a seal between thesecond mask seal assembly and the mask body.

Preferably the first seal of the first seal assembly and the seal on thesecond side of the first clip of the first seal assembly are integrallyformed and joined together across the bridging portion of the firstclip, and/or

the second seal of the second seal assembly and the seal on the secondside of the second clip of the second seal assembly are integrallyformed and joined together across the bridging portion of the secondclip.

Preferably a mask assembly comprising the mask body and the first sealassembly or the second seal assembly is a nasal mask or a full facemask.

Preferably the first side of the second clip has a longer perimeterlength than the first side of the first clip, the second seal beinglarger than the first seal.

Preferably the first side of the second seal has a longer perimeterlength than the first side of the first seal.

Preferably the first and second seals are different types of seals, thefirst and second seals being one of a cannula seal, a nasal seal, amouth seal and a full face seal.

Preferably the first mask seal assembly and the second mask sealassembly releasably attach to a rear perimeter of the mask body.

Preferably the rear perimeter of the mask body defines an area beingmore than ten times the area of the mask body inlet.

Preferably the bridging portion of the first clip spaces the second sideof the first seal outwards from the perimeter or periphery of the maskbody by at least 10 mm, or the bridging portion of the second clipspaces the second side of the second seal outwards from the perimeter orperiphery of the mask body by at least 10 mm.

Preferably the mask body defines a hollow space for receiving orcovering a user's nose or mouth or both.

In another aspect, the present invention broadly consists in a maskassembly for use as part of an apparatus for supplying a flow ofrespiratory gases to a user, comprising:

a mask body having an inlet through which said flow of respiratory gasesare provided to the interior of said mask body, the inlet adapted to beconnected to a gases conduit,

a mask seal assembly comprising a seal of a flexible material and a clipof a rigid material,

said seal having a first side and a second side, the first side of saidseal being shaped to approximately match the contours of a user's faceand in use substantially seal against a user's face, said second sideattached to said clip,

said clip providing an interface extending substantially the fullperimeter or periphery of the mask seal assembly for releasablyattaching the mask seal assembly to the mask body, and

an inner cushion located between the clip and said first side of theseal.

Preferably the clip comprises a bridging portion spanning outwards fromthe perimeter or periphery of the mask body to space at least the secondside of the seal outwards from the perimeter or periphery of the maskbody.

Preferably the inner cushion is located between the bridging portion andthe first side of the seal.

Preferably the clip comprises a channel in the bridging portion, a firstside of the inner cushion in use supporting the first side of the seal,and a second side of the inner cushion being received in the channel.

Preferably the seal is attached to a first side of the clip and a secondside of the clip releaseably attaches to the mask body, and the bridgingportion spans between the first and second sides of the clip.

Preferably the seal assembly comprises a second seal of flexiblematerial attached to the second side of the clip for forming a sealbetween the mask seal assembly and the mask body.

Preferably the bridging portion and said seal are sized according to oneof a series of sizes, each one of the series of sizes suitable forsealing against a differently sized user's face.

Preferably the mask body is adapted for use with a plurality of saidseal assemblies, at least one said seal assembly having a said bridgingportion, each said seal assembly having a said seal sized according toone of a series of sizes, each one of the series of sizes suitable forsealing against a differently sized user's face, and said second side ofthe clip of each said seal assembly being the same or similar to bereleasably attached to the mask body.

Preferably the seal and the second seal are integrally formed and joinedtogether across the bridging portion.

Preferably the seal and the second seal are integrally formed and joinedtogether across the bridging portion via a runner across or through thebridging portion.

Preferably the mask assembly comprises an inner cushion located betweenthe mask body and said first side of the seal.

Preferably the mask assembly comprises a channel in the mask body, afirst side of the inner cushion in use supporting the first side of theseal, and a second side of the inner cushion being received in thechannel in the mask body.

Preferably the bridging portion has an outward dimension that is thesame or similar around the perimeter or periphery of the mask body.

Preferably the bridging portion has an outward dimension that variesaround the perimeter or periphery of the clip.

Preferably the outward dimension of the bridging portion is larger at abottom portion of the seal assembly and smaller at an upper portion ornasal bridge region of the seal assembly.

Preferably the bridging portion tapers from a first outward dimension inthe bottom portion of the mask assembly to a second outward dimension inthe upper portion or nasal bridge region of the mask assembly.

Preferably each said seal assembly in the said plurality of sealassemblies has a bridging portion with a first outward dimension in thebottom of the mask assembly and a second outward dimension in the upperportion of the mask assembly and the first outward dimension is greaterthan the second outward dimension, and the second outward dimension ofeach said seal assembly is the same or similar, and the first outwarddimension of each said seal assembly is different to the first outwarddimension of the other said seal assemblies in said plurality of sealassemblies, the first outward dimension of each said seal assembly sizedto be suitable for sealing against a differently sized user's face.

Preferably the bridging portion extends rearward away from a front ofthe mask body towards a user's face in use.

Preferably the mask body is adapted for use with a plurality of the sealassemblies, at least one said seal assembly having a said bridgingportion, each said seal assembly having a seal of a different typecomprising one of a cannula seal, a nasal seal, a mouth seal and a fullface seal, and the second side of the clip of each said seal assemblybeing the same or similar to be releasably attached to the mask body.

Preferably the mask seal assembly releasably attaches to a rearperimeter of the mask body.

Preferably the rear perimeter of the mask body defines an area beingmore than ten times the area of the mask body inlet.

Preferably the bridging portion spaces the second side of the sealoutwards from the perimeter or periphery of the mask body by at least 10mm.

Preferably the mask body defines a hollow space for receiving orcovering a user's nose or mouth or both.

In another aspect, the present invention broadly consists in a mask sealassembly for use as part of an apparatus for supplying a flow ofrespiratory gases to a user, comprising:

a seal of flexible material and a clip of rigid material,

the seal having a first side and a second side, the first side of theseal being shaped to approximately match the contours of a user's faceand in use substantially seal against a user's face, the second sideattached to said clip,

the clip providing an interface extending substantially the fullperimeter or periphery of the seal assembly, the clip having a firstside and a second side, the second side of the seal being attached tothe first side of the clip, and the second side of the clip forreleasably attaching the mask seal assembly to a mask body,

wherein the clip comprises a bridging portion spanning between the firstand second sides of the clip to space at least a portion of the secondside of the seal outwards from the perimeter or periphery of the secondside of the clip.

Preferably the clip comprises a channel in the bridging portion forreceiving an inner cushion for supporting the first side of the seal inuse.

Preferably the seal assembly comprises a second seal of flexiblematerial attached to the second side of the clip for forming a sealbetween the mask seal assembly and a mask body.

Preferably the bridging portion and the seal are sized according to oneof a series of sizes, each one of the series of sizes suitable forsealing against a differently sized user's face.

Preferably the seal and the second seal are integrally formed and joinedtogether across the bridging portion.

Preferably the seal and the second seal are integrally formed and joinedtogether across the bridging portion via a runner across or through thebridging portion.

Preferably the bridging portion has an outward dimension that is thesame or similar around the perimeter or periphery of the mask sealassembly.

Preferably the bridging portion has an outward dimension that variesaround the perimeter or periphery of the clip.

Preferably the outward dimension of the bridging portion is larger at abottom portion of the seal assembly and smaller at an upper portion ornasal bridge region of the seal assembly.

Preferably the bridging portion tapers from a first outward dimension inthe bottom portion of the mask assembly to a second outward dimension inthe upper portion or nasal bridge region of the mask assembly.

Preferably the bridging portion extends rearward away from a front of amask body to which the mask assembly is attached in use and towards auser's face in use.

Preferably the mask seal assembly is adapted to releasably attach to arear perimeter of a mask body defining a hollow space for receiving orcovering a user's nose or mouth or both and having an inlet throughwhich the flow of gases are provided to the interior of the mask body.

Preferably the rear perimeter of the mask body defines an area beingmore than ten times the area of the mask body inlet.

Preferably the bridging portion spaces the second side of the sealoutwards from the perimeter or periphery of the second side of the clipby at least 10 mm.

The term “comprising” is used in the specification and claims, means“consisting at least in part of. When interpreting a statement in thisspecification and claims that includes “comprising”, features other thanthat or those prefaced by the term may also be present. Related termssuch as “comprise” and “comprises” are to be interpreted in the samemanner. The invention consists in the foregoing and also envisagesconstructions of which the following gives examples.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described above and as further described below. Of course, it is tobe understood that not necessarily all such objects or advantages may beachieved in accordance with any particular embodiment of the invention.Thus, for example, those skilled in the art will recognize that theinvention may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments of the presentinvention will become readily apparent to those skilled in the art fromthe following detailed description of the preferred embodiments havingreference to the attached figures, the invention not being limited toany particular preferred embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described withreference to the accompanying drawings. The appended drawings areschematic, not necessarily drawn to scale, unless otherwise indicated,and are meant to illustrate and not to limit embodiments of theinvention.

FIG. 1 illustrates three differently sized prior art mask frames andcorresponding seal assemblies.

FIG. 2 is a perspective view of the nasal mask of FIG. 1.

FIG. 3 is an exploded view of the nasal mask of FIG. 1.

FIG. 4a is a perspective view of the mask seal assembly of the nasalmask of FIG. 1.

FIG. 4b is a perspective view of the seal clip of the mask seal assemblyof the nasal mask of FIG. 1.

FIG. 5 is a perspective view showing the mask body and the mask sealassembly of the nasal mask of FIG. 1, with the mask seal assemblyremoved from the mask body.

FIG. 6 is a sectional view on line X-X of the nasal mask of FIG. 2.

FIG. 7 is a block diagram of a humidified continuous positive airwaypressure system as might be used in conjunction with the mask assemblyof the present invention.

FIG. 8 is a cross sectional view of a mask assembly according to oneembodiment of the present invention.

FIGS. 9A to 9C are part sectional views of a lower portion of a seriesof three differently sized mask assemblies.

FIGS. 10A to 10C are part sectional views of a lower portion of threealternative mask assemblies each having a ‘large’ sized seal assembly.

FIGS. 11A to 11C are part sectional views of a lower portion of threealternative mask assemblies each having a ‘medium’ sized seal assembly.

FIG. 12 is a diagram showing part sectional views of a common mask bodyand a range of mask seal assemblies for attachment to the common maskbase.

FIG. 13 is a perspective view of a mask assembly comprising the presentinvention with section cut away to show a lower portion of the maskassembly in cross section.

FIGS. 14A to 14D show cross sections of alternative seal arrangementsfor forming a seal between a seal assembly and a mask body of a maskassembly comprising the present invention.

FIGS. 15A and 15B are part sectional views of a lower portion of twoalternative mask assemblies each with a first seal and a second sealjoined together across a bridging portion of a seal clip.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

It will be appreciated that the mask assembly as described in thepreferred embodiment of the present invention can be used in respiratorycare generally or with a ventilator, but will now be described belowwith reference to use in a humidified Continuous Positive AirwayPressure (CPAP) system. It will also be appreciated that the presentinvention can be applied to various forms of mask assembly including,but not limited to, nasal masks and full face masks that cover both theuser's nose and mouth.

With reference to FIG. 7 a humidified CPAP system is shown in which apatient 1 is receiving humidified and pressurised gases through apatient interface 2 connected to a supply conduit 3. It should beunderstood that CPAP is used generically and includes a range ofvariants including VPAP (Variable Positive Airway Pressure) and BiPAP(Bi-level Positive Airway Pressure) and numerous other forms ofrespiratory therapy.

Supply conduit 3 is connected to the outlet 4 of a humidificationchamber 5 that contains a volume of water 6. Supply conduit 3 maycontain a heater or heater wires (not shown) which heat the walls of theconduit or the gases in the conduit to reduce condensation of humidifiedgases within the conduit. Humidification chamber 6 is preferably formedfrom a plastics material. The contents of the chamber are heated by aheater. For example the chamber may have a highly heat conductive base(for example an aluminium base) which is in direct contact with a heaterplate 7 of humidifier 8. Humidifier 8 is provided with control means orelectronic controller 9 which may comprise a microprocessor basedcontroller executing computer software commands stored in associatedmemory.

Controller 9 receives input from sources such as a user interface ordial 10 through which a user of the device may, for example, set a value(e.g., a preset or predetermined value) of humidity or temperature ofthe gases to be supplied. The controller may also receive input fromother sources; for example temperature and/or flow velocity sensors 11and 12 through connector 13 and heater plate temperature sensor 14. Inresponse to the user set humidity or temperature value input via dial 10and the other inputs, controller 9 determines when (or to what level) toenergise heater plate 7 to heat the water 6 within humidificationchamber 5. As the volume of water 6 within humidification chamber 5 isheated, water vapour begins to fill the volume of the chamber above thewater's surface and is passed out of the humidification chamber 5 outlet4 with the flow of gases (for example air) provided from a gases supplymeans or blower 15 which enters the chamber through inlet 16. Exhaledgases from the patient's mouth are passed directly to ambientsurroundings in FIG. 1.

Blower 15 is provided with variable pressure regulator or a variablespeed fan 21. The fan draws air or other gases through blower inlet 17.The speed of the variable speed fan 21 is controlled by electroniccontroller 18 (or alternatively the function of controller 18 couldcarried out by controller 9) in response to inputs from controller 9.

Mask Assembly

A mask assembly 2 according to the present invention is described withreference to FIGS. 8 to 13. FIG. 8 shows a mask comprising a mask body30. The mask body includes an inlet 22 for receiving a flow of gasesinto the mask assembly. The mask body preferably includes features forsecuring the mask assembly in position on the user's face. For example,the embodiment of FIG. 8 includes a forehead rest 31 to assist withcorrect placement of the mask assembly against the user's face, and aclip 33 for attachment to headgear. Headgear may also be attached tofeatures of the forehead rest. The mask body may include other knownfeatures, for example vent holes 25 for venting expired gases and air,and a channel 66 for receiving an inner cushion (not shown) forsupporting the seal 43.

A seal assembly 40 comprising a seal 43 of a flexible material and clip42 of a rigid material is attached to a rear side of the mask body. Afirst side of the flexible seal contacts a user's facial features inuse. A second side of the flexible seal is attached to the clip. Theseal assembly is releasably attached to the mask body 30 by the clip.Preferably the clip extends substantially the full perimeter of the maskseal assembly. The clip is rigid compared to the seal material andprovides a convenient interface for releaseably attaching the flexibleseal to the mask body. For example, the clip is manufactured frompolycarbonate, ABS, nylon, acetyl or other similar rigid plastic.Alternatively the clip may be made from a high Shore A hardnesssilicone. For example, a silicone with a Shore A hardness of 90 mayprovide sufficient rigidity. The clip and mask body may be manufacturedfrom the same material type. The seal is formed from rubber or othersuitable flexible, resilient material. Preferable the seal is formedfrom silicone with a Shore-A hardness of less than 60. Preferably theseal is made from silicone with a Shore A hardness of 20-40.

From the above mentioned materials, the difference in rigidity of theclip material (rigid) and the seal material (flexible) will beappreciated. For example, polycarbonate has a Young's modulus ofapproximately 2 GPa, whereas the Young's modulus of a rubber or othersuitable material for use as the flexible seal is in the order of 1 to 5MPa.

The seal generally provides a flexible perimeter about the perimeter orperiphery of the mask body. The seal surrounds an opening to the insideof the mask assembly. A nasal mask assembly seals against a user's facearound the user's nose, the seal opening covering the user's nose. Afull face mask seals against a user's face around the users nose andmouth, the seal opening covering both the user's nose and mouth.

The clip has a bridging portion 50 that spans outwards from theperimeter or periphery of the mask body 30. The bridging portion spacesat least a portion of the second side of the flexible seal 43 outwardsfrom the perimeter or periphery of the mask body to which the clip isattached.

The mask body 30 may be used with a conventional seal assembly asdisclosed in the prior art, for example as illustrated in FIG. 4A. Wherea larger mask may be used by a larger user, the same mask body 30useable with the conventional seal assembly may be used together with aseal assembly comprising a clip with a bridging portion 50. The bridgingportion 50 allows a larger flexible seal 43 to be attached to the maskbody 30, as illustrated in FIG. 8.

The present invention allows a single mask body 30 to be used for arange of differently sized users. For example, a range of differentlysized seal assemblies may be provided. Each seal assembly may have aclip including a bridging portion 50. The bridging portion of each sealassembly may be a different size and each clip may be attached to adifferent size flexible seal. A smallest seal assembly in a range ofdifferently sized seal assemblies may not include a bridging portion,the smallest seal assembly being a standard or conventional type sealassembly, for example as illustrated in FIG. 4A.

For supply to a user, a packaged interface product may include a singlemask body, and a plurality of these seal assemblies, each of a differentsize with at least one of the seal assemblies having a bridging portion.The package may include instructions for selection and assembly of theseal assemblies to the mask body 30. The plurality of different sizeseal assemblies may be varied according to their size, by the size andarrangement of the bridging portion, the placement of an inner cushionand other aspects of variation described in this specification.

The range of seal assemblies for use with a single mask body preferablyeach have an identical or at least similar connection portion or sidefor attaching to the single mask body.

The clip with bridging portion expands a mask body to a larger size foruse with a larger flexible seal. The mask body may be used with a firstseal assembly comprising a flexible seal and clip without a bridgingportion, for example as shown in FIG. 9C. The same mask body may be usedwith one or more seal assemblies each comprising a flexible seal andclip with a bridging portion to expand the mask body for use with alarger seal. A series of seal assemblies may be provided, each sealassembly in the series having a clip with a progressively largerbridging portion and corresponding larger flexible seal. A plurality ofseal assemblies with clips each having differently sized bridgingportions may be provided to achieve a range of mask assemblies, forappropriate selection by a user, as illustrated in FIGS. 9A and 9B.

As shown in FIG. 8, preferably the bridging portion of the clip has anoutward dimension D that varies around the perimeter or periphery of themask body. As shown in FIG. 8, preferably the outward dimension of thebridging portion is larger at a bottom portion of the clip and smallerat an upper portion of the clip. Alternatively, the bridging portion mayhave an outward dimension the same or similar around the periphery ofthe mask body.

The outward dimension of the bridging portion of a number of differentseal assemblies may be the same in a particular portion of the mask bodyperimeter or periphery to which the clips are attached. For example, arange of different seal assemblies each may comprise a clip withbridging portion having a similar or the same outward dimension in thenasal bridge region, and each clip having a different outward dimensionoutside the nasal bridge region.

A mask according to the present invention may include a mask body havinga forehead rest, for example as shown in FIG. 8. It can be advantageousfor a mask having a forehead rest to have a range of different sealassemblies each comprising a clip with bridging portion having a similaror the same outward dimension in the nasal bridge region. With each clipin the range of seal assemblies having a similar outward dimension inthe nasal bridge region, the distance between the top of the sealassembly and the forehead rest remains the same across the range ofdifferent sized seal assemblies. This is preferred as the distance theforehead rest is above the top of the mask body can be sized to besuitable for use with a range of different sized seal assemblies. Bycomparison, in a less preferred embodiment of the present invention,each seal assembly has a clip with bridging portion having asubstantially constant outward dimension around the full parameter ofthe seal assembly. For larger seals, the distance between the top of theseal and the forehead rest therefore decreases.

The distance between the top of the seal and the forehead rest ideallyshould increase for increasing sized users. With each seal in a range ofseals having the same bridging portion outward dimension in the nasalbridge region, the distance between the forehead rest and the top ofeach seal is the same, which is preferred to the previously describedless preferred embodiment.

Preferably the clip has a bridging portion that tapers from a firstoutward dimension in a lower section of the seal to a second outwarddimension in the nasal bridge region, the first dimension being greaterthan the second dimension.

The embodiment of FIG. 8 is illustrated without an inner cushion betweenthe mask body 30 and the flexible seal 43. Preferably the mask assemblycomprises an inner cushion between the mask body 30 and the flexibleseal 43, or an inner cushion between the clip and the flexible seal.

FIGS. 10A to 10C illustrate alternative clips with a bridging portion inthe lower portion of the seal assembly for providing a ‘large’ sizedseal 43 compared to other sealing assemblies. In each embodiment ofFIGS. 10A to 10C, an inner cushion is located between the clip and thefirst side of the flexible seal 43. Preferably the inner cushion islocated between the clip bridging portion and the first side of theflexible seal.

Preferably the bridging portion comprises a channel 67 for receiving andlocating a side of the inner cushion at the clip. The channel may extendaround a full circumference of the clip, or the channel may extendaround a portion of a circumference of the clip. For example, thechannel may extend around the clip outside the nasal bridge region onlyfor use with a cushion having a raised nasal bridge region similar tothe configuration of the inner cushion described in US2010/0006101.

In the embodiment of FIG. 10B, the bridging portion extends outwardlyfrom the mask body 30 and also rearward, away from the general plane ofthe mask body, towards the user in use. The mask body and seal assemblycombine to provide a cavity for surrounding the user's nose, or mouth orboth. The rearward extension of the clip bridging portion increases thedepth of the cavity provided by the mask assembly. For example, thedepth DB of the cavity provided by the assembly of FIG. 10B with arearward extension of the clip bridging portion is deeper than the depthDA of the cavity of the assembly of FIG. 10A with a clip bridgingportion that does not extend rearward. The rearward extension of thebridging portion 50 of the embodiment of FIG. 10B spaces the second sideof the seal 43 rearward from the perimeter or periphery of the maskbody. For larger sized users, for example a user with a larger nose, adeeper internal cavity provided by the mask body and seal clip mayreduce the likelihood of the user's nose touching an inside surface ofthe mask body compared to a mask assembly comprising a smaller seal 43.Extending the second side of the flexible seal 43 rearwards by providinga clip with a rearward extending bridging portion provides a deepercavity to receive the user's nose compared to a mask assembly having aclip without a rearward extending bridging portion.

In the alternative embodiment of FIG. 10C, a deeper mask cavity iscreated compared to the embodiment of FIG. 10A by providing a deeperinner cushion and flexible seal for sealing against the user's face. Theembodiments of FIGS. 10A and 10C each have the same shaped clip withbridging portion.

FIGS. 11A to 11C illustrate alternative clips with a bridging portion inthe lower portion of the seal assembly for providing a ‘medium’ sizedseal compared to other sealing assemblies. For example, the bridgingportions 50 of the embodiments of FIGS. 11A to 11C have a smalleroutward dimension compared to the bridging portions 50 of theembodiments of FIGS. 10A to 10C so that the seal 43 of the embodimentsof FIGS. 11A to 11C are smaller than the seals of the embodiments ofFIGS. 10A to 10C. And the bridging portions 50 of the embodiments ofFIGS. 11A to 11C each provide a seal 43 that is larger than the seal ofthe illustrative embodiment comprising a clip with a bridging portionhaving a smaller outward dimension, or an embodiment comprising a clipwithout a bridging portion, for example the illustrative embodiment ofFIG. 9C.

In the embodiment of FIG. 11A, an inner cushion 41 is located betweenthe mask body 30 and the first side of the flexible seal 43, similar inconcept to the aforementioned nasal mask illustrated in FIGS. 1-6. Achannel 66 is formed in the mask body by two spaced apart members 76 and77. A side of the inner cushion 41 in contact with the mask body isreceived in the channel 66.

FIGS. 11B and 11C illustrate embodiments similar to the embodiment ofFIG. 10A described above, with the inner cushion located between theclip 42 and the flexible seal 43. However the outward dimension of theclip bridging portion of the ‘medium’ seal assemblies of FIGS. 11B and11C is smaller than the outward dimension of the large' clip of theembodiment of FIG. 10A.

Due to the smaller bridging portion of the clip of the medium sealassembly of FIG. 11B, the side of the inner cushion in contact with theclip may be reduced in cross section compared to the inner cushion ofthe large seal assemblies of FIGS. 10A to 10C. In the alternativeembodiment of FIG. 11C, a channel for receiving the cushion in the sealassembly is formed by material of the flexible seal that contacts auser's face in use, and material of a second flexible seal 44 on theother side of the bridging portion 50. The second flexible seal 44 isdiscussed below.

One embodiment of the present invention comprises a packaged maskassembly product including a single mask body and a plurality of sealassemblies of different sizes for use with the single mask body. Forexample, a mask package may include a single mask body 30 and a firstseal assembly 540, a second seal assembly 640, and a third seal assembly740, as shown in FIG. 12. The first seal assembly has a clip 542 andseal 543. The clip 542 does not have a bridging portion, the second side5432 of the seal attached to the clip is not spaced outwards of the maskbody when the seal assembly is attached to the mask body. For example, aportion of the material forming the seal 543 also forms a seal againstthe mask body. The mask assembly comprising the mask body 30 and thefirst seal assembly 540 may also include an inner cushion 541 locatedbetween the first side 5431 of the seal 542 and the mask body 30. Theinner cushion is received in the channel 66 of the mask body 30. Themask assembly comprising the first seal assembly 540 is most suited tousers with smaller facial features compared to other users.

Where the first seal assembly is not large enough for a particular user,that user may chose to use the second seal assembly 640. The second sealassembly has a clip 642 and seal 643. The clip 642 has a bridgingportion 650 to space the second side 6432 of the seal attached to theclip outwards of the mask body when the seal assembly is attached to themask body. The bridging portion has an outward dimension Dm to space thesecond side of the seal outwards from the mask body by a distance. Thebridging portion 650 of clip 642 allows a larger seal to be used withthe body 30 by comparison with the seal of the first seal assembly 540.For example, the seal 643 attached to clip 642 of the second sealassembly 640 may be taller and wider in places compared to the seal 543of the first seal assembly 540.

The mask assembly comprising the mask body 30 and the second sealassembly 640 may also include an inner cushion 641. In the illustratedexample, the inner cushion 641 is located between the first side 6431 ofthe seal 643 and clip 642. The inner cushion 641 is received in thechannel 667 of the clip 642.

Where the second seal assembly is not large enough for a particularuser, that user may chose to use the third seal assembly 740. The thirdseal assembly has a clip 742 and seal 743. The clip 742 has a bridgingportion 750 to space the second side 7432 of the seal attached to theclip outwards of the mask body when the seal assembly is attached to themask body. The bridging portion has an outward dimension DL to space thesecond side of the seal outwards from the mask body by a distance. Bycomparison, the outward dimension of the bridging portion 750 of thethird seal assembly 740 is larger than the outward dimension of thebridging portion 650 of the second seal assembly 640. The bridgingportion 750 of clip 742 allows a larger seal to be used with the body 30by comparison with the seal of the second seal assembly 640. Forexample, the seal 743 attached to clip 742 of the third seal assembly740 may be taller and wider in places compared to the seal 743 of thesecond seal assembly.

The mask assembly comprising the mask body 30 and the third sealassembly 740 may also include an inner cushion 741. In the illustratedexample, the inner cushion 741 is located between the first side 7431 ofthe seal 743 and clip 742. The inner cushion 741 is received in thechannel 767 of the clip 742.

It can be seen from FIG. 12 that incorporating a bridging portion intothe clip of a plurality of seal assemblies, each one with a differentsized bridging portion, provides for a series of differently sized sealassemblies for use with a common mask body. A series of seal assemblies,each with a bridging portion with an increased outward dimensionprovides a series of increasing sized seal assemblies for use with acommon mask body.

The seal of a seal assembly generally provides a flexible perimeterabout the perimeter or periphery of the mask assembly. The sealsurrounds an opening to the inside of the mask assembly. A second sealdescribed as being larger than a first seal has a larger perimeter andopening than the first smaller seal. For example, the present inventionmay comprise a nasal mask package comprising a common mask body and aseries of differently sized seal assemblies, each having a perimeteradapted to seal about a user's nose, the user's nose being received inan opening of the seal. Alternatively, the present invention maycomprise a full face mask package comprising a common mask body and aseries of differently sized seal assemblies, each having a perimeteradapted to seal about a user's nose and mouth, the user's nose and mouthbeing received in an opening of the seal.

Furthermore, a second seal described as being larger than a first sealnot only has a larger perimeter and opening than the first smaller seal,but preferably also has a deeper seal assembly depth. The depth of aseal assembly is indicated in FIG. 12 by dimensions D1, D2 and D3 forthe three different sized seals illustrated. As shown, the depth of theseal assemblies increases for increasing seal sizes.

A large range of users can be accommodated by providing three differentsize mask seals for use with a common body. The three different sizeseals may conveniently be labeled as small, medium and large. A nasalmask suitable for a range of smaller users may have a seal height fromthe bridge of the nose to the philtrum area of around 45 mm. A nasalmask suitable for a range of medium sized users may have a seal heightfrom the bridge of the nose to the philtrum area of around 54 mm.According to the present invention, the difference in height between thesmall seal and the medium seal is accommodated by the outward dimensionof the bridging portion of the clip of the medium seal assembly. A nasalmask suitable for a range of larger sized users may have a seal heightfrom the bridge of the nose to the philtrum area of around 58 mm.Similarly, according to the present invention, the difference in heightbetween the small seal and the large seal is accommodated by the outwarddimension of the bridging portion of the clip of the large sealassembly, the outward dimension of the bridging portion of the clip ofthe large seal assembly being greater than the outward dimension of thebridging portion of the clip of the medium seal assembly.

A series of differently sized seal assemblies may comprise a feature orfeatures that are common to more than one seal assembly in the series.For example, a plurality of seal assemblies in a series of sealassemblies may each have the same or a similarly shaped nasal bridgeregion.

The present invention allows for a range of different types of seals tobe used with a common mask body. For example, a common mask body may beused with a nasal seal assembly comprising a clip and seal for sealingaround the nose of a user. The same mask body may also be used with afull face seal assembly comprising a clip and a seal for sealing aroundthe nose and mouth of a user.

The seal of each seal assembly is attached to a first side of the sealassembly clip. A second side of the clip attaches to the common maskbody. Each seal assembly clip has an identical or at least similarconnection portion or second side for attaching to the common mask body.The clip of each seal assembly has a different first side to allowdifferent types of seals to be used with the common mask body. Theportion of the clip spanning between the first and second sides of theclip allows a different size or type of seal to be used with the commonmask body. For example, the seal and first side of the clip of a fullface seal assembly has a longer perimeter length than the seal and firstside of the clip of a nasal seal assembly. The difference in perimeterlengths of the first sides of the clips of the full face and nasal sealassemblies is achieved by the clip of the full face seal assembly havingbridging portion spanning between the first and second sides of the clipwith a larger outward dimension than the clip of the nasal sealassembly. For example, the clip of the nasal seal assembly may have abridging portion with a smaller outward dimension than the clip of thefull face seal assembly, or the clip of the nasal seal assembly may nothave a bridging portion, the second side of the seal of the nasal sealassembly not being spaced outwardly from the perimeter of the commonmask body.

A range of different types of seals, each with a clip having a differentfirst side allows many different types of seals to be used with a commonmask body. For example the common mask body may be used with a cannulaseal assembly, a nasal seal assembly, a mouth seal assembly and a fullface assembly.

As described above, a sealing assembly according to one embodiment ofthe present invention comprises a rigid clip having a bridging portionfor spacing the second side of the flexible seal in contact with auser's face outwards from the perimeter of the mask body. The flexibleseal is attached to a first side of the clip. A second side of the clipattaches to the mask body. The bridging portion of the clip spansbetween the first and second sides of the clip.

Preferably the seal assembly further comprises a second flexible seal 44attached to the second side of the clip for forming a seal between theseal assembly 40 and the mask body 30, as shown in FIGS. 10A to 14B. Thebridging portion 50 spans between a first seal 43 for forming a sealagainst a user's face, and a second seal 44 for forming a seal betweenthe seal assembly and the mask body 30.

The first and second seals may be integrally formed, for example in aninjection moulding process, the first and second seals integrally formedand joined together via a runner across or through the bridging portion.Alternatively, the first and second seals may be joined by overmouldingthe seal material from the first flexible seal to the second flexibleseal across the bridging portion as illustrated in FIGS. 15A and 15B.Alternatively, the first and second seals may be separately formed, forexample by providing multiple insertion points, a multiple stagemoulding process, or by a runner subsequently removed.

Various second seal configurations for sealing between the seal assemblyand the mask body are illustrated in FIGS. 14A to 14D. As illustrated inFIG. 14A, the second seal 44 has a bearing surface 51 extending aroundthe perimeter of the clip. The second seal bearing surface 51 faces acorresponding bearing surface 52 on the mask body. The seal bearingsurface and the mask bearing surface are in contact when the sealassembly is attached to the mask body in a butting engagement. When theseal assembly 40 is attached to the mask body 30, the second seal 44 atthe bearing interface is compressed so that a sealing interface isformed between the seal assembly and the mask body.

Preferably, the clip has a raised ridge 45 running around the insideperimeter of the clip. The second seal 44 is compressed when the clip isattached to the mask body by being squashed between the raised ridge 45and the mask body bearing surface 52 when the seal assembly 40 isattached to the mask body 30.

To assist with creating a good seal between the seal assembly and themask body, a continuous rim 53 may be provided on the seal bearingsurface 51. The rim provides a small contact area in contact with themask body bearing surface 52. The small contact area allows a relativelyhigh compression of the rim, and therefore effective seal, for arelatively small seal assembly to mask body engagement force.

The alternative sealing arrangement illustrated in FIG. 14B comprises aseal that slides against a corresponding lateral member of the mask bodyduring engagement of the seal assembly to the mask body. For example, awall 77 forming a side of a channel 66 in the mask body for receivingthe inner cushion as shown in FIG. 11A extends rearward to contact thesecond seal 44 when the seal assembly 40 is attached to the mask body30. Preferably the second seal 44 comprises a raised rim 53 on thesurface 51 that contacts the lateral member 77. The rim provides a smallcontact area in contact with the mask body bearing surface 52 in contactwith the seal. The small contact area allows a relatively highcompression of the rim, and therefore effective seal, for a relativelysmall seal assembly to mask body engagement force.

The alternative sealing arrangement illustrated in FIG. 14C comprises alip 54 that bears against an end of a lateral member of the mask body30. For example, a wall 77 forming a side of a channel 66 in the maskbody for receiving the inner cushion as shown in FIG. 11A extendsrearward to contact the lip 54 of the second seal 44 when the sealassembly 40 is attached to the mask body 30.

The alternative sealing arrangement illustrated in FIG. 14D is similarto the arrangement of FIG. 14B but includes two sealing rims 53 insealing contact with a surface of the mask body.

The present invention has been described with reference to a nasal maskassembly. However, the present invention may equally be applied to othermask assemblies, for example full face masks that cover a user's noseand mouth.

Although certain preferred embodiments and examples have been discussedherein, it will be understood by those skilled in the art that thepresent invention extends beyond the specifically disclosed embodimentsto other alternative embodiments and/or uses of the invention andobvious modifications and equivalents thereof. In addition, while anumber of variations of the invention have been shown and described indetail, other modifications, which are within the scope of thisinvention, will be readily apparent to those of skill in the art basedupon this disclosure. It is also contemplated that various combinationsor sub-combinations of the specific features and aspects of theembodiments may be made and still fall within the scope of theinvention. Accordingly, it should be understood that various featuresand aspects of the disclosed embodiments can be combined with orsubstituted for one another in order to form varying modes of thedisclosed invention. Thus, it is intended that the scope of the presentinvention herein disclosed should not be limited by the particulardisclosed embodiments described above, but should be determined only bya fair reading of the present disclosure, including the appended claims.

What we claim is:
 1. A mask assembly comprising: a mask body; and a maskseal assembly.